What is it about ?
A doctor can take a blood test during a check-up, check-up or when symptoms are present. In most cases, this blood test will also assess liver function and possible liver damage.
To do this, we measure the concentration of certain enzymes. Enzymes are substances that stimulate the transformation of certain molecules in our body. The most important liver enzymes (haematic enzymes) are
- Alanine aminotransferase (ALT or ALAT or GPT or TGP),
- Aspartate aminotransferase (AST or ASAT or GOT or TGO),
- Alkaline phosphatases (PAL),
- Gamma-glutamyltransferases (gamma-GT or γGT).
One or more of these tests can be abnormal in many conditions. The degree of abnormality of different liver tests can give an indication of the nature of the condition.
How to recognize it?
In many cases, an abnormal liver function test does not show any symptoms. The condition responsible for abnormal tests may, however, be manifested by
- Yellowing of the skin and whites of the eyes
- Darker urine
- Itches,
- A pain,
- Tiredness,
- Weight loss.
What can you do ?
Being overweight and drinking alcohol can interfere with liver testing. It is therefore important to maintain a healthy lifestyle.
How does your doctor assess a liver function test?
High levels of ALT or GPT
This elevation can be caused by:
- Acute or chronic inflammation of the liver (hepatitis);
- Obesity;
- Diabetes;
- A tumor of the liver;
- Obstruction of the bile ducts (for example from a gallstone)
- Alcohol consumption ;
- Medication.
In people with slightly increased ALT (GOT) levels (less than 3 times the upper limit of normal), the doctor should assess the role of alcohol and obesity.
In case of daily alcohol consumption of more than 40 grams in a woman and more than 60 grams in a man, the doctor will take into account the damage to the liver induced by alcohol and advise, if necessary, some lifestyle adjustments. A check will be carried out after 12 weeks. If the rate has not dropped, additional tests will be done, initially via an ultrasound and other blood tests.
In people with a greatly increased ALT (GOT) level (more than 3 times the upper limit of normal), additional examinations will be systematically carried out, and they will be carried out urgently in the presence of symptoms.
High levels of alkaline phosphatase (ALP)
These enzymes are not only produced by the liver, but also by the intestines, bones and placenta in pregnant women. An abnormal level can therefore indicate a disease of the liver or bile, but also bone damage. The rates are rarely increased due to intestinal disorders. If necessary, further blood tests and an ultrasound or MRI will be done.
High levels of gamma-GT
This elevation may indicate a biliary obstruction inside or outside the liver, but also the effect of drugs, alcohol or certain nutritional factors. A slight elevation, without an increase in other liver values, does not usually point to serious liver disease. Additional examinations and follow-up are often unnecessary.
If alcohol seems to play a role, the doctor will suggest having a blood test again after a period of complete abstinence.
High levels of AST or GPT
This test risks giving erroneous values and is therefore no longer used routinely. AST (GPT) is mainly found in the liver, heart muscle (myocardium) and skeletal muscles, but also in the kidneys and red blood cells. AST (GPT) is primarily used in conjunction with ALT to assess the cause of liver damage.
Want to know more?
- Ultrasound here Where to find on this page of Cliniques St Luc UCL
- MRI, here, Where to find on this page of Cliniques St Luc UCL
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